The present invntion relates to a compressor for coil springs, in particular for facilitating the mounting and removal of suspension springs of automobile vehicles.
It more particularly relates to spring compressors of the type comprising two jaws provided for the insertion therebetween of two-spread apart coils of the spring to be compressed and mounted in facing relation to each other, one jaw being fixed, the other slidable on a longitudinally split guide tube, and an actuating screw located on the axis of the tube for controlling the displacements of a slide which is connected to the slidable jaw.
Compressors of this type must be capable of being used for mounting or removing springs of various shapes and dimensions, i.e. must be capable of receiving interchangeable jaws of a range of dimensions which are adapted to the diameters of the springs. They must also be capable of resisting large forces and in particular axial forces such as those that the coils of an automobile vehicle suspension spring are capable of exerting thereon.
In order to satisfy the first requirement and permit adapting as desired the jaws to the springs, the jaws are generally formed by clamps or claws having a U-shape or a horse-shoe shape, the size of which corresponds to that of the coils it is desired to insert therebetween and provided with removable means for connection to the slide through a longitudinal slot in the guide tube. Unfortunately, the assembly between the jaw and the slide is liable to break under the effect of the force exerted on the claw.
It has therefore been proposed to associate with a slide placed inside the guide tube a sleeve surrounding the latter and slidable along the tube. The claw is in this case detachably mounted on the sleeve. There is less risk of breakage of the assembly between the claw and the slidable element but this risk remains. On the other hand, the friction is distinctly increased owing to the friction of the sleeve on the tube and may even in some cases prevent the sliding of the sleeve, in particular when the claws are of large size.
Further, U.S. Pat. No. 3,520,527 discloses a vice whose fixed and slidable jaws each comprise holding arms in one piece with a body which is bored at the diameter of a guide tube containing an axial screw for driving the slidable jaw through a screw-threaded radial finger member. The connection arranged in this way is complicated and relatively fragile.